Help! Trying to diagnose AC issues

[Marshy]

I've been having intermittent underperforming ac for a few months now. Doesn't blow very cold and sometimes won't cool at all, but sometimes it works normal.
When acting up, both the front and rear show the same symptom.
Checked my refrigerant pressures, at 96 ambient, vent blowing at 70, was about 30psi low and 150 psi high.
To me that high side seems extremely low. Another observation, when I removed the high port dust cap, it had some pressure under it.
I want to try and charge a can or two of r1234yf and see if it improves performance but I'm hesitant because I don't want to overcharge it.

Does anybody have some pointers?

 

[Deadman]

If you buy the parts store AC charge cans, its FULL of sealant and that will eventually plug up ll the small orfaces and make it a future nightmare. fyi...

 

[Marshy]

If you buy the parts store AC charge cans, its FULL of sealant and that will eventually plug up ll the small orfaces and make it a future nightmare. fyi...

I'm definitely going to use pure r1234yf with no stop leak additives. It's available at my flaps.

 

[LazSlate]

150 psi is generally for 112 ambient but many factors may be in play.
150/30 is out of balance. Both low would be low coolant but when the high and low are out of balance its either

- High too high and low to low = TXV (expansion valve) or orifice tube blocked or restricted.
- High too low and low too high = TXV stuck open or not sealing

I would venture to say your expansion valve or the tube is blocked. Also with 30 psi low you are near the freezing point so if the day is humid your coil could be freezing up hence the intermittent cooling.

 

[wakeboarder]

I've been having intermittent underperforming ac for a few months now. Doesn't blow very cold and sometimes won't cool at all, but sometimes it works normal.
When acting up, both the front and rear show the same symptom.
Checked my refrigerant pressures, at 96 ambient, vent blowing at 70, was about 30psi low and 150 psi high.
To me that high side seems extremely low. Another observation, when I removed the high port dust cap, it had some pressure under it.
I want to try and charge a can or two of r1234yf and see if it improves performance but I'm hesitant because I don't want to overcharge it.

Does anybody have some pointers?

Do you have a 2018? If so, there was a TSB about some type of AC contamination from the factory.

 

[BMW2FORD]

Both pressures seem low for a R1234yf system. More like 60 on the low and 175-200 on the high is normal when the system just starts to cool off a hot car at that ambient temp assuming humidity is also high. If you got a burst of pressure taking the cap off then for sure the Schrader valve is leaking and might be the entire problem of why it’s low. I did see some stores selling pure cans and no sealant R1234yf. Maybe buy a kit to top it off through the low side then with the cap off fill the valve with water. If you see any bubbles, it’s for sure leaking. This stuff below is also helpful to find leaks,

Big Blu Subzero Micro Leak Detector 1Qt https://a.co/d/37cR0Dp

 

[KSC 2019 XLT]

Your symptoms sounds like my 2019 Expy. Took to Ford dealership 4 times over the course of 3 summers (4th time being right now and they still have it - been there since last Monday) and they are finally replacing the compressor and evaporator all under warranty. Should be ready this week. If you are still under warranty, take it in.

 

[Marshy]

Update...so I charged my system with about 12 oz of r1234yf using the honeywell service cans. The system began to cool normally again and has worked normally for a couple of weeks.
I guess I have diagnosed a slow leak. Let the games begin...

 

[wakeboarder]

Update...so I charged my system with about 12 oz of r1234yf using the honeywell service cans. The system began to cool normally again and has worked normally for a couple of weeks.
I guess I have diagnosed a slow leak. Let the games begin...

My 2019 had a similar occurrence. I also added a can of R1233yf and it seems to have taken care of the issue. The vents are now blowing in the 20° to 30° range when set to max. I only had a low side gauge. It started at 25 psi and the 8 oz can took it to 35 psi. My ambient was about 85°F.

Has it happened again or did you find the leak?

 

[Soliyou]

The rear AC unit has been the culprit in many cases. If you didn’t use UV dye, get a refrigerant sniffer.

 

[ColoradoJon]

Just had my AC go out this past week. Had it already scheduled at the dealer and they said it was empty. Couldn't find the leak. Pretty random at 63k to not have a clear reason. Just went on a 1600 mile trip and had no issues.

 

[wakeboarder]

Just had my AC go out this past week. Had it already scheduled at the dealer and they said it was empty. Couldn't find the leak. Pretty random at 63k to not have a clear reason. Just went on a 1600 mile trip and had no issues.

I added 8 oz at the end of June. It lasted until the beginning of August. The AC shop couldn’t find the issue, so they added dye. I think it is a very slow leak. They told me to come back if it starts blowing warm again.

 

[Mr Big]

Update...so I charged my system with about 12 oz of r1234yf using the honeywell service cans. The system began to cool normally again and has worked normally for a couple of weeks.
I guess I have diagnosed a slow leak. Let the games begin...

Check your caps to make sure the gasket is still good, or you don't have one. Just like home A/C systems, Valves tend to have small seepage, causing the freon to leak out over months. So, we put rubber gaskets in the cap to keep that tiny little leak stopped. I did this on my Ford Excursion when the pressures were low every season. Never had an issue for years after the gasket install.

 

[ncszot84]

Hi,
2019 Exp max. I'm having similar issues with a slow leak not showing up on dye or sniffer, multiple checks by the shop. It takes about 6 months to lose a full charge and been through that twice. Shop replaced the shrader vales. Other than the valve cap gasket idea (which I will try) have others tracked this down to another slow leak spot? I've read the under dash evaporator, rear evaporator, and compressor front seal...mostly stuff cant see. Thanks,

 

[wakeboarder]

Hi,
2019 Exp max. I'm having similar issues with a slow leak not showing up on dye or sniffer, multiple checks by the shop. It takes about 6 months to lose a full charge and been through that twice. Shop replaced the shrader vales. Other than the valve cap gasket idea (which I will try) have others tracked this down to another slow leak spot? I've read the under dash evaporator, rear evaporator, and compressor front seal...mostly stuff cant see. Thanks,

Mine is still working fine since the recharge. I’ll report back when it recurs.

 

[2018ExpyPlatinum]

I've never been overly impressed with the AC in this vehicle. I've complained on here several times. Compared to my wife's RAV4, it sucks. I've had it checked by my dealer twice and been told "it's fine, no issues". It did seem better late summer this year. I am due for service in a few months. Maybe I'll ask again with my new dealer and see what happens.

 

[Mr Big]

I've never been overly impressed with the AC in this vehicle. I've complained on here several times. Compared to my wife's RAV4, it sucks. I've had it checked by my dealer twice and been told "it's fine, no issues". It did seem better late summer this year. I am due for service in a few months. Maybe I'll ask again with my new dealer and see what happens.

My 2019 Platinum freezes me out. And my wife's 2021 Explorer is the same. Both systems cool down fast and maintain 70 degrees or lower on even the hottest Florida summer months. I'm not sure why yours is not doing its job, unless you have a leak or somehow you are getting heat mixed with the A/C. My 2000 Excursion had an issue with vacuum, where the heat valve was staying open causing the A/C to blow warm air. I fixed the leak, and it went back to the same results as my newer Fords.

 

[2018ExpyPlatinum]

@Mr Big .......I really don't know either, nor do they. I've kinda just excepted the fact that it just doesn't do the job. I have another (AZ) summer to go thru, and then I think it's gone....sadly. I won't keep it beyond the extended warranty period....I don't think.

 

[kahewitt02]

My 2018 expedition has never had cold a/c…everything has been replaced…recently brought it in, sat for 2 weeks and they tell me I need new heater hoses, coolant leak. Going to try and do it myself this weekend and save $1049.

 

[Going_Going_Gone]

I've never been overly impressed with the AC in this vehicle. I've complained on here several times. Compared to my wife's RAV4, it sucks. I've had it checked by my dealer twice and been told "it's fine, no issues". It did seem better late summer this year. I am due for service in a few months. Maybe I'll ask again with my new dealer and see what happens.

The AC in our 2019 has been outstanding too. My previous Ford was a 2010 F-150 crew cab and the AC in it was pitiful.